This guide explains how to configure OBS for the screen recording required during the ACSC 2026 Finale. You only need to complete the initial setup once; OBS will remember these settings the next time you open it.
Download OBS#
Download and install OBS (Open Broadcaster Software) for your operating system from the official OBS website.
Initial setup#
- Open OBS after installing it.
- OBS will display the Auto-Configuration Wizard. Close the wizard without running it.
- Select Settings in the bottom-right corner of the main window.
Video settings#
Open the Video section and enter the following values:
| Setting | Value |
|---|---|
| Base (Canvas) Resolution | 1920x1080 |
| Output (Scaled) Resolution | 1280x720 |
| Downscale Filter | Bicubic (Sharpened scaling, 16 samples) |
| FPS Type | Integer FPS Value |
| Integer FPS Value | 1 |
Output settings#
Open the Output section, set Output Mode to Advanced, and select the Recording tab.
Do not change Recording Path. The existing path is where OBS will save your recordings, so make a note of it.
Recording#
| Setting | Value |
|---|---|
| Type | Standard |
| Generate File Name without Space | Disabled |
| Recording Format | Hybrid MP4 (.mp4) |
| Video Encoder | x264 |
| Audio Encoder | FFmpeg AAC |
| Audio Track | Track 1 only |
| Rescale Output | Disabled |
| Custom Muxer Settings | Leave empty |
| Automatic File Splitting | Split by Time |
| Split Time | 60 min |
Encoder#
| Setting | Value |
|---|---|
| Rate Control | VBR |
| Bitrate | 1000 Kbps |
| Use Custom Buffer Size | Disabled |
| CRF | 23 |
| Keyframe Interval | 2 s |
| CPU Usage Preset | veryfast |
| Profile | (None) |
| Tune | (None) |
| x264 Options | Leave empty |
Select OK to apply the settings.
OBS will automatically create a new recording file approximately every hour without interrupting the recording. Keep and submit all the files produced during the competition.
Optional: disable audio capture#
Audio is not required for the competition recording. To avoid accidentally recording conversations:
- Keep FFmpeg AAC selected as the audio encoder and keep Track 1 enabled. OBS requires at least one audio track when using the standard recording mode.
- Open Settings → Audio and set every Global Audio Device to Disabled.
- Mute or remove every source shown in the OBS Audio Mixer.
- Make a short test recording and confirm that it contains no sound.
This leaves a silent audio track in the recording while preventing audio from being captured.
File name and overwrite settings#
Open the Advanced section, find the Recording settings, and enter the following values:
| Setting | Value |
|---|---|
| Filename Formatting | %CCYY-%MM-%DD %hh-%mm-%ss |
| Overwrite if file exists | Disabled |
These settings give every recording a timestamped filename and prevent an existing recording from being overwritten. If you stop and restart the recording, OBS will save the restarted recording as a separate file.
Add your display#
- In the main OBS window, select + in the Sources panel.
- Select Display Capture and confirm with OK. On macOS, this source may be called macOS Screen Capture.
- If the source properties window opens, select the display you will use from the Display menu and confirm with OK.
- Your screen will appear in the OBS preview. Right-click it and select Transform → Fit to screen.
Allow screen recording on macOS#
macOS may ask you to allow OBS to record your screen. Open System Settings → Privacy & Security → Screen & System Audio Recording, enable OBS.app, and follow any additional instructions shown by macOS.
Start and stop recording#
To start recording, select Start Recording. Check that the button becomes active and its label changes to Stop Recording.
To finish, select Stop Recording and wait for the button to return to its original state. This may take several seconds.
If OBS or the computer crashes, reopen OBS and start a new recording as soon as possible. The Hybrid MP4 format is designed to leave an interrupted recording recoverable, although its unfinished final portion may be missing. Keep both the interrupted recording and the new recording.